I am setting up a Green Screen in my studio. The angled walls are white(cant change that) and the other straight walls are builder beige. It is in an upper level long room. Should I paint these walls a different color so I do not get issues with color spill/reflection from the Green Screen? New at GS in my home studio, but the TV studio I worked at had white walls next to the GS walls. I was thinking of painting them a grey. I edit there too. Also, there is a window behind the GS I will be setting up, since it is a portable GS. Does it have to be completely blacked out?